Lightning on Earth releases ‘killer electrons’ in orbit

Lightning on Earth releases ‘killer electrons’ in orbit

Written by Kate Graham Shaw

Lightning strikes in the atmosphere can trigger a powerful rain of “killer electrons” in low Earth orbit, creating streams of harmful radiation, a new study suggests. Scientists previously thought that killer electrons only appeared in Earth’s far outer radiation belts, but one study found that nature communications Additionally, I noticed that lightning also loosens them on the closer inner belts.

“These high-energy particles can damage not only spacecraft, but also humans in space,” said study co-author Lauren Bloom, an astrophysicist at the University of Colorado Boulder. “Knowing when there are very high-energy electrons in the inner radiation belt helps us know when to avoid it.”

Electron precipitation occurs when charged particles held in place by Earth’s magnetic field are released from rest in one of the planet’s donut-shaped radiation belts. Examining data from NASA’s SAMPEX mission, which tracked charged particles, the new study’s lead author, Max Feinland, then an undergraduate at UW Boulder, discovered that “microbursts” (1996-1996-1996 I noticed something odd about the measurements (a rapid surge in high-energy electron precipitation recorded by 2013). 2006. After designing an algorithm to find these spikes in the data, Feinland was surprised to see measurements from the inner radiation belt. Many scientists thought it hosted only lower-energy, slower electrons. Feinland and Bloom, who was Feinland’s research advisor at the time, soon began to wonder about potential causes. “People knew that there was lightning-induced dropout of electrons in the inner belt,” Feinland said. “But we’ve never seen anything conclusive about electrons traveling this fast.”

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The researchers compared the microburst data to the National Lightning Detection Network dataset and found a statistical likelihood that the bursts in the inner belt actually coincided with lightning flashes. The electromagnetic waves emitted by the latter travel from the atmosphere up the Earth’s magnetic field lines to the region of the internal radiation belts, and their energy is sufficient to expel high-energy electrons from magnetic confinement.

Stephen Morley, a space weather scientist at Los Alamos National Laboratory, said the team’s findings are compelling because no one seems to have made such a connection before. He added that there are data constraints in this area of ​​research, as few measurements have been taken since SAMPEX ended 20 years ago. But he says the study is “very interesting despite the very limited data.” In fact, many other questions arise. ”

These discoveries are a “wake-up call” about how Earth and space weather are intertwined, Blum said. This relationship can affect the ozone layer, atmospheric chemistry, and even climate. “You can’t study the dynamics of the Sun-to-Earth and radiation belts separately,” she says. “We also need to understand what’s happening beneath our atmosphere and surface weather systems.”